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R&D Pipeline
Lysigen has a pipeline of lysins for topical, vaginal, lung, and prosthetic joint infections. The platform has produced lysins active against ESKAPE pathogens, including multidrug-resistant Gram-negative bacteria.
LYSG101 - Staphylococcal Lysin
LYSG101 is an engineered chimeric lysin targeting Staphylococcus aureus, including drug-resistant strains. In preclinical studies it was roughly ten times more potent than exebacase, the most clinically advanced staphylococcal lysin. A single dose improved survival in lethal intraperitoneal and intravenous mouse models at doses as low as 0.25 mg/kg. It also reduced lung bacterial burden more than 1,000-fold in neutropenic mice lung infection. Against more than 300 clinical isolates of S. aureus and coagulase-negative staphylococci, it inhibited 90% of strains (MIC90) at 2 µg/mL (0.125 µg/mL in serum). The lysin killed target bacteria within 15 minutes, cleared MRSA biofilms, and showed no cytotoxicity. No resistance emerged over 100 serial passages. These data are published open access and were selected as an Editor's Pick in Antimicrobial Agents and Chemotherapy: "LYSG101: a potent chimeric lysin with therapeutic potential for combating Staphylococcus aureus infections," Vol. 70, No. 6. DOI: 10.1128/aac.01730-25. In 2025, LYSG101 was administered under an FDA expanded-access (compassionate-use) protocol for a drug-resistant prosthetic joint infection unresponsive to standard care, and was well tolerated.
StaphLycide - Lysin for Eczema
StaphLycide is an engineered, room-temperature-stable lysin with high activity against Staphylococcus aureus. S. aureus colonizes the lesional skin of approximately 70-90% of eczema patients and rises in prevalence during flares, making it a key target for restoring skin health.
AczePHx is a medical-device spray formulated with StaphLycide, designed to rebalance the skin microbiome in eczema patients.
C. acnes Lysins for Acne
Lysigen has developed and patented a portfolio of highly active lysins targeting Cutibacterium acnes, the organism most closely associated with acne vulgaris. These lysins kill C. acnes rapidly and act through a structural mechanism that leaves bacteria little opportunity to develop resistance. This is unlike the antibiotics that dominate current acne therapy, whose prolonged use has driven widespread C. acnes resistance and disrupted the wider skin microbiome.
Developed for Lysigen's DermPHx product line, these lysins are precise topical candidates that rebalance the skin microbiome without driving resistance.
Gram-Negative Lysins for Lung and Invasive Infections
Lysigen has developed a range of engineered lysins active against multidrug-resistant Gram-negative ESKAPE pathogens, including Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, which are among the most urgent threats in antimicrobial resistance. Engineering is central to this program: the Gram-negative outer membrane normally shields the cell wall from externally applied lysins, so these constructs are designed to overcome that barrier. They retain activity across a range of biological matrices, supporting their development for lung and other invasive infections.
Gardnerella vaginalis Lysins for Bacterial Vaginosis
Lysigen has developed a range of engineered lysins highly active against Gardnerella vaginalis, the keystone organism of bacterial vaginosis (BV) and the scaffold of its characteristic biofilm. This work forms part of a Gates Foundation-funded discovery program awarded to Lysigen's parent company, Precisio Biotix Therapeutics, aimed at the principal pathogens behind BV. The lysins reduce G. vaginalis and clear its biofilm while sparing the protective Lactobacillus community that maintains a healthy vaginal microbiome.